Wednesday, 10 February 2016

Record low ice extent in the Arctic this winter

Unusually
warm Arctic winter stuns scientists with record low ice extent for
January

Right
about now, Arctic sea ice should be building up toward its annual
maximum, making most of the region impenetrable to all but the most
hardened icebreakers. Instead, January and indeed much of the winter
so far has been unusually mild throughout large parts of the Arctic.

A freak
storm brought
temperatures to near the freezing point, or 32 degrees Fahrenheit,
near the North Pole for a short time in late December and early
January, and other storms have repeatedly acted like space heaters
plopped on top of the globe, turning nascent sea ice to slush and
eventually, to open water.

Nothing
is as it should be for this time of year across a wide swath of the
Arctic. Alaska has had not yet had a winter, with record warmth
enveloping much of the state along with anemic snow depth.

Sea
ice is virtually absent from the Barents and Kara Seas, which
constitute a large swath of the Atlantic Arctic, located northeast
of Scandinavia and north of the Russian mainland.

“For
the Arctic this is definitely the strangest winter I’ve ever
seen," said Mark Serreze, the director of the National
Snow and Ice Data Center (NSIDC) in Boulder, Colorado, which tracks
sea and land ice around the world.

Arctic
sea level pressure and air temperature anomalies during January 2016.

IMAGE:
NSIDC.

For
example, New York City received more snow on Friday morning alone —
2.5 inches — than Fairbanks, Alaska, which set a record for the
lowest amount of snow between Dec. 1 and Jan. 31 since records began
there in 1915.

Fairbanks
had just 1.8 inches of snow during the period, which was more than 20
inches below average, and about the same amount of snow that
fell in New York City in one hour during a blizzard on Jan. 22-23.

Near-surface
air temperatures across the Arctic Ocean averaged a staggering
13 degrees Fahrenheit, or 6 degrees Celsius, above average during
January, according to the NSIDC.

In
Norway's Svalbard Archipelago, the northernmost permanent civilian
community on Earth, temperatures were unusually toasty during
January, following a deadly December that featured a destructive
avalanche.

During
the period from Jan. 5 to Feb. 3, the average temperature there was
23.5 degrees Fahrenheit, according to meteorologist Bob Henson
of Weather
Underground.

That
is 19 degrees Fahrenheit above average for the period, which is an
extremely high anomaly for a 30-day period.

To
put it another way, the coldest air temperature recorded in Svalbard
during that period was 10.6 degrees Fahrenheit, or minus-11.9 degrees
Celsius, which was milder than the average January high temperature
of 8.6 degrees Fahrenheit, or minus-13 degrees Celsius.

Sea
ice record during an "absurdly warm" month

The
milder than average conditions led January to have the lowest Arctic
sea ice extent on record since the satellite era began in 1979, the
NSIDC found.

According
to an NSIDC report released Thursday, the monthly average sea ice
extent for January was 42,500 square miles below the previous record
low in 2011, and about 405,000 square miles below the 1979-2000
average.

For
perspective, that departure from average is equivalent to missing a
region of ice the size of the states of Texas, New Mexico, Maryland
and New Hampshire combined.

The
longterm trend for January sea ice extent is now a decline of 3.2%
per decade, the NSIDC said.

Due
to manmade global warming, sea ice has been in a near free-fall,
while Arctic air temperatures have increased at twice the rate of the
rest of the world due to a phenomenon known as Arctic
amplification.

Arctic
warming is having profound effects all around the region, from the
loss of coastal villages and threats to iconic wildlife such as the
polar bear and walrus.

There is debate within the scientific
community about whether Arctic warming is influencing weather
patterns well beyond the Arctic, such as across
the eastern U.S. and
in Europe.

Blame the Arctic Oscillation?

The
record low ice extent for the month had a lot to do with the way that
weather patterns set up across the Arctic, Serreze told Mashable in
an interview.

The
entire Arctic was “just absurdly warm, I’ve never seen anything
like that,” Serreze said.

Serreze
pointed to a pattern of air pressure known as the Arctic Oscillation
as a major driver of January's Arctic warmth and low sea ice.

The
Arctic Oscillation, or AO, is a pattern of air pressure differences
between the Arctic and the midlatitudes. It swung into an extreme
negative phase — meaning there were higher than average air
pressure values over the Arctic and lower than average air pressure
values over the mid-latitudes — during the first three weeks of
January, dipping to near-historic lows.

The
NSIDC provided a more zoomed-in view of January's prevailing weather
pattern across the Arctic, stating in a press release there was
higher than average air pressure located from north central Siberia
into the Barents and Kara sea regions, while lower than average air
pressure dominated across the northern North Atlantic and northern
North Pacific.

The
airflow between and around these high and low pressure areas helped
pump mild air into the Arctic, while interfering with the
manufacturing of extremely cold air.

The
result was as if someone had switched the northern hemisphere's
refrigerator onto a lower setting.

“The
Arctic is behaving very oddly this winter," Serreze said.

"The
Arctic is behaving very oddly this winter," Serreze said.

How
the Arctic Oscillation, and the weather across the Arctic region in
general, is interacting with a strong
El Niño event in
the tropical Pacific Ocean is still an open question, Serreze said

The
El Niño is also helping to reconfigure weather patterns from
Australia to the U.S. and beyond, but its relationship with the
Arctic has only recently begun to be investigated.

“The
question is how are these two things possibly conspiring there?”
Serreze said.

He
said even a late season burst of ice growth will put the sea ice
cover in a vulnerable position going into the summer, since that new
ice will be thin, and therefore more susceptible to melting.

“Things
are not looking very good,” Serreze said of the warm winter and
what it means for the upcoming melt season.

A
record melt season is not a guarantee, he noted. Last winter, Arctic
sea ice set a record for the lowest sea ice maximum, but the melt
season did not end up at a record low, though it came close.